Problem: Multiply the following complex numbers, marked as blue dots on the graph: $( e^{7\pi i / 4}) \cdot (4 e^{\pi i / 6})$ (Your current answer will be plotted in orange.)
Answer: Multiplying complex numbers in polar forms can be done by multiplying the lengths and adding the angles. The first number ( $ e^{7\pi i / 4}$ ) has angle $\frac{7}{4}\pi$ and radius $1$ The second number ( $4 e^{\pi i / 6}$ ) has angle $\frac{1}{6}\pi$ and radius $4$ The radius of the result will be $1 \cdot 4$ , which is $4$ The angle of the result is $\frac{7}{4}\pi + \frac{1}{6}\pi = \frac{23}{12}\pi$ The radius of the result is $4$ and the angle of the result is $\frac{23}{12}\pi$.